This may be of no use whatsoever. I had an ancient Volvo in a 45' Adams which I sold years ago. It was a great engine and, true to the old dictum of 'one horsepower per foot, it was, I think, 43 hp. , and, it was sufficient.
I would fire it up, and like a good friend with a bad habit, it would start to smoke. I would accept this as merely a Volvo foible when the smoke was light-black in colour...and I would change the filter whenever it started to look like a wet season sky..ie black-black.
In all the years I had the boat, I wished it wouldn't smoke, mainly because I would be a little embarrassed in marinas. But, when the inevitable occurred and someone made comment, I got used to saying "....but it is a Volvo". This would be met with knowing looks, nods of the head and an invitation to share a beer or a coffee.
It seems that older Volvo marine plants are genetically predisposed to smoking. In defence of Volvos, it never let me down: and I bought five new Volvo motor cars in a row between 1980 and 2004.
I hope your engine is just being an old Volvo and I sincerely hope it won't let you down. As for the smoke limiter, I feel a little sceptical. But who knows? Let us know if you decide to install one and whether it then is a success.
"if at first you don't succeed....Redefine success"!